A self-contained light pencil is a convenient means with which one can determine the presence of an electrically conducting material. Typically, such a light pencil can be used as a learning aid for self-testing. A simple example will suffice. If one were presented with the multiple choice statement:
A bird can
a. fly. [ ] PA1 b. swim. [ ] PA1 c. run. [ ]
and if the answer square following answer "a" were electrically conductive and the answer squares following answers "b" and "c" were nonconductive, then an individual using the light pencil can easily test himself. Were he to select answer "a" by touching the contiguous square with the light pencil, the light contained within the light pencil will be illuminated because the light pencil has contacted conductive material. However, if he selects either of answers "b" or "c", the light is not illuminated and he immediately realizes that he has selected an incorrect response.